Avalanche Forecast
Issued: Dec 15th, 2020 4:00PM
The alpine rating is , the treeline rating is , and the below treeline rating is Known problems include Wind Slabs and Deep Persistent Slabs.
swerner,
Avalanche Canada
Wind slabs may exist on all aspects due to the changing winds. However; the freshest and possibly the most reactive ones could be triggered on northeast to southeast slopes.
Summary
Confidence
Low - Uncertainty is due to limitations in the field data. Forecast snowfall amounts are uncertain.
Weather Forecast
Fast-moving frontal systems bring new snow and a strong SW flow to the region through the forecast period.
Overnight Tuesday: New snow 5-15 cm with a strong southwest wind. Freezing level 600 m.
Wednesday: 5-10 cm of snow. Moderate and gusty southwest wind. Freezing level 1000 m.
Thursday: Cloudy with some sunny periods. Flurries 2-5 cm. Strong southwest wind.
Friday: Mix of sun and cloud. Strong southwest wind and freezing level 900 m.
Avalanche Summary
No new avalanches reported on Tuesday.
A wind slab avalanche likely stepped down to the weak faceted grains described in the snowpack summary, forming a large avalanche near Smithers within the past few days.
Data in this region is very sparse. Please considering sharing your observations to the Mountain Information Network; even just a photo of your day helps. Thank you to those that have already submitted this winter.
Snowpack Summary
Wind from variable directions have affected the snow surface at and above treeline, forming wind slabs on all aspects. Strong southwest wind and small amounts of new snow are forecast until Friday. These slabs may overly a melt-freeze crust from early December, which may have weak and sugary faceted grains growing around it.
At the base of the snowpack sits the early-November crust with weak faceted grains below. These faceted grains have formed large avalanches in both the south and north of the region within the past week.
Snowpack depths vary substantially with aspect, elevation, and wind exposure. Below treeline the terrain may still be below the threshold for avalanches.Â
Terrain and Travel
- Recent wind has varied in direction so watch for wind slabs on all aspects.
- Be careful with wind loaded pockets, especially near ridge crests and roll-overs.
- If triggered, wind slabs avalanches may step down to deeper layers resulting in larger avalanches.
- Avoid shallow, rocky areas where the snowpack transitions from thick to thin.
Problems
Wind Slabs
Wind from variable directions has formed wind slabs on all aspects. 10-20 cm of new snow and strong wind from the southwest is forecast until the weekend, so the freshest slabs are expected to be on northwest to northeast to southeast aspects. Loose-dry sluffing may be seen from steep terrain.
Aspects: All aspects.
Elevations: Alpine, Treeline.
Likelihood
Expected Size
Deep Persistent Slabs
Weak faceted grains near the base of the snowpack have the potential of forming large and destructive avalanches. The most likely place to trigger this layer would be on shallow and rocky slopes. Smaller wind slab avalanches would also have the potential of stepping down to this layer.
Aspects: All aspects.
Elevations: Alpine, Treeline.
Likelihood
Expected Size
Valid until: Dec 16th, 2020 4:00PM
